What might cause all the warning lights on my dash to be lighting up

my 1992 volvo 240 seems to be having problems with the alternator working inconsistently. ive measured its output which stays at 12 volts when the car is off and varies when the car is running from 12 to about 13.5 volts when floored in neutral. to my understanding its supposed to be at about 14 when the engine is on. when the volts are at 12 all my warning lights on the dash turn on and my headlights dim and wiper blades slow down. while i drive the warning lights turn on and off at will and it seems that cranking up the rpms will get them to shut off but that doesnt always work. ive driven like this for about 6 months and the car hasnt broken down but it feels like a ticking time bomb. recently the warning lights wouldnt shut off at all for a few days straight so i snooped around under the hood and noticed that the battery ventilation tubes werent installed so i put them in and ever since the warning lights rarely even flicker on and the battery puts out 13.5 volts consistently. would the battery ventilation have anything to do with the alternators performance or is it just coincidence that everything has been working properly since then?

Must’ve been the annular eclipse.

OR grounding.
While ‘snooping’ under the hood you probably did a good thing, but which thing we won’t know, by moving, bumping, wiggling and otherwise sharpening a ground point somewhere.

WE got to see a perfectly centered ‘‘ring of fire’’ eclipse out here, how 'bout youall ?